Phosphorescent device



Oct. 17, 1944.

G. T. SCHMIDLING PHOSPHORESCENT DEVICE Filed Nov. 18, 1941 XZMMQQM fiTTOR/VEY Patented Oct. 17, 1944 UNITED STATES PATENT. OFFICErnosrnonasosn'r mavros Gilbert '1. Schmidling, New York, N. Y.Application November 18, 1941, Serial No. 419,521

19 Claims.

The present invention relates generally to phosphorescent devices andmore particularly to an improved phosphorescent surface and coatingtherefor.

The value of phosphorescent lighting in protecting against hazards andin preventing accidents and injuries is being appreciated more and more.Cars and trucks are stopped on roadways and streets without lights, andhallways, garages, steps and other places are left unlighted forsubstantial periods of time, generally at night. The number of accidentsand injuries resultin from unlighted objects and unlighted passagewaysare enormous. In war time, such accidents are greatly increased due toblackout periods and elimination of ordinary lights to prevent beingseen by the enemy flying over in planes. Phosphorescent lighting,surfaces are clearly visible at short distances but not at substantialdistances; hence, they may be made to serve the purpose of makingobstacles visible without being seen from planes.

The general principle of phosphorescent lighting is the provision of asurface adapted to absorb light while exposed to it and to glow or emitlight after the energizing light is extinguished. Some phosphorescentmaterials will slow for a few seconds and others for a few hours afterbeing energized. Likewise, the intensity varies with different materialsand decreases somewhat rapidly during the afterglow period. There are nomaterials known which have sufficient light intensity or sufllcientafterglow periods to be entirely satisfactory for all requirements.Constant effort, particularly durin the present war period, is beingmade to improve phosphorescent materials and surfaces in'this respect.

The present invention aims to overcome the above difllculties and toprovide an improved phosphorescent surface which will give a greaterluminous intensity and a longer afterglow with a given phosphorescentmaterial. In addition, the invention provides an improved phosphorescentcoating having high efllciency and durability.

An object of the present invention is to provide an improvedphosphorescent'surface.

Another object of the invention is to provide an improved phosphorescentcoating,

Another object of the invention is to provide a phosphorescent surfacewhich has a longer afterglow and a higher luminous intensity.

Another object of the invention is to increase the period of afterglowand the luminous intensity obtained with a material.

Another object of the invention is to provide a phosphorescent surfacehaving greater a permanence and durability.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described, orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description and is shown in the accompanying drawing,forming a part of the specification, wherein Fig. 1 is a top plan viewof a surface of a sheet or article having the present coating appliedthereto, the upper coatings being broken away to show the lower ones andthe surface of the article;

Fig. 2 is a sectional view along the line 2-2 of Fig. 1, the thicknessof the coatings being greatly exaggerated:

Fig. 3 is a top plan view of an improved surface adapted to increasetheintensity and afterglow of a phosphorescent coating:

Fig. 4 is a sectional view along the line 4-4 of Fig; 3;

Fig. 51s a top plan view of a disk-shaped de vice having the improvedsurface of Figs. 3 and 4;

Fig. 6 is a top plan view of the surface of an article illustrating analternate embodiment of the improved phosphorescent surface; and

Fig. 7 is a sectional view of another embodigiven phosphorescent ment ofthe invention.

Referring again to the drawing and more particularly to Figs. 1 and 2,there is shown an improved phosphorescent coating for surfaces to belighted. The base I is intended to illustrate, as an example, a sheetmetal plate for the front or back of a car or truck. It, could, be usedequally well to light any other obstacle or hazard. It is also to beunderstood that the coating shown on the plate may be applied directlyto the surface of any article or object where a phosphorescent coatingis desired. In the preferred embodiment; three coatings are applied tothe surface of the article I; first the coating 2, then a second coating3 of phosphorescent material and. a third protective coating 4. I havefound that by applying the three coatings consecutively and by bakingeach one on before applying the succeeding coating, improved resuits areobtained: hence, I prefer to follow such procedure, although it is notessential in all cases. The temperature and period of baking may bevaried to a considerable extent. However, as an example, good resultsmay be obtained by'baking the respective coatings for a period of aboutfifteen minutes at a temperature of about 160 centigrade.

Both the constituents and the proportions thereof in the composition ofthe coatings may be varied but the following examples give excellentresults. For the first coating 2 I prefer to use:

4 Parts (A) Melamine 80 (n) ifiibutyl phthalate 15 (C) Toluol(enoughtothin) 5 (D) Titanium oxide (enough to give white I color) 20(E) Aluminum stearate 5 For the second coating 3 I prefer to use:

Parts (A) Melamine 80 (B) Dibutyl phthalate 15 (C) Toluol (enoughtothin)5 (D) Strontium hydroxide or a proper proportion of another suitablephosphores- The first coating 2 gives a base on which a coating ofphosphorescent material may be securely adhered and in addition gives alight background which cooperates with the phosphorescent coating toobtain a maximum absorption and emission of light. The coating 3 is moreparticularly a phosphorescent material in a substantially transparentcarrier. Strontium hydroxide is given as the phosphorescent materialbutit is to be understood that any other phosphorescent material may besubstituted therefor. The aluminum stearate is an important but not anessential element. It renders the solution alkaline, which prevents orminimizes the effect of attack by moisture on the coating due toexposure to weather and normal atmospheric conditions. Acids are formedwhen the coating is attacked by moisture and the presence of an alkalinestabilizer neutralizes and prevents the acid from damaging thephosphorescent coating, thus preserving the effectiveness of thecoating. Other suitable stabilizers are calcium borate, glycerolmonostearate and calcium stearate. The aluminum stearate also acts as asuspending medium for the other constituents of the first and tlenessand cracking of the coatings are minimized.

As an alternative for the coating 4 disclosed above, a thin sheet ofmaterial such as Cellophane, polystyrene, methyl methacrylate, or nbutymethaorylate may be utilized with excellent results. The sheet orcoating is preferably applied under heat and pressure over thephosphorescent coating.

An important object of the invention is to increase the period ofafterglow and the luminous intensityduring the afterglow ofphosphorescent surfaces. This is achieved in part by the wmbination ofcoatings described above and also by the constructions illustrated inFigs. 3, 4 and 5 of the drawing where a sheet of metal I is shown inFigs. 3 and 4 with a phosphorescent coating '1' thereon, preferablythough not necessarily the coatings illustrated and described withreference to Figs. 1 and 2. A sheet of metal I is pleated or folded asshown in Figs. 3 and 4 so that the phosphorescent coating is on a seriesof joined V-shaped or trough-like surfaces 8. The sides of the V-shapedsurfaces should be at a comparatively small angle with respect to eachother to obtain the best results. Excellent results may be obtained withangles from five to fifteen degrees. The purpose of the small angles isto have some of the rays from one surface impinge on the adjacentsurface and vice-versa. In this way the surfaces are continually excitedby each other and the afterglow continues for a longer period. Theintensity is also much greater. The incident rays as well as the emittedrays increase the brightness of the surface. In one way, the operationmay be compared to flashlights with their beams crossing. There is adecided increase in intensity at the point where the beams cross.Likewise, if the two flashlight beams are directed against a wall, theintensity is greater with both beams on the same spot than with one. Byhaving the Joined v-shaped surfaces, both effects are achieved by thenumerous phosphorescent particles acting more or less like tinyflashlights, as shown by the arrows at 9 with reference to a singleparticle. Thus both the intensity and the period of the afterglow aregreatly increased. If desired, the pleated sheet may be expanded duringexposure to light to facilitate absorption thereof and rapidenergization. While troughlike creases and depressions are shown inFigs. 8 and 4, the same general eflect could be obtained by otherprotuberances and depressions; for example, protuberances anddepressions like the surface of a waiiie iron.

In Fig. 5, a round disk II is shown with pleats ll radiating from thecenter thereof. The principle and operation of the surface are the sameas disclosed with reference to Figs. 3 and 4.

Another embodiment for obtaining a result similartothat inFigs.3to5isshowninFig. 6,!17.

forming cracks in the coating I of phosphorescent material. This may beachieved by including with the constituents thereof solvents that dry atdiflerent rates. By including one solvent that dries several timesfaster than mother, the two contract at different rates of speed andgive a crackle surface. The fine cracks disperse the light laterally andhence increase the intensity and the period of the afterglow. The deviceof Fig. 6 may be coated in advance and quickly secured by adhesive,nailing or otherwise to anykind of surface. In certain instancesit mightbe difflcult to apply adhesive to' the fluted or corrugated material ofFigs. 3 and 5 and then to apply it by means of the adhesive to asurface. The device of Fig. 6 provides a result similar to Figs. 3 and 5but in an easily attachable flat surface. If desired, the device of Fig.6 may be fluted as shown in Fig. 4.

Considerable time and trouble are involved in applying the severalcoatings of the present invention to obstacles such as steps in garages,walls, parts of battleships, et cetera. In order to facilitate suchapplications and to increase the general application of the invention,an alternati've embodiment is illustrated in Fig. 7. A base material I,preferably of thin aluminum, is provided and the coatings 2, 3' and 4applied thereto as described with reference to Figs. 1 and 2.Thereafter, a sheet of fabric or other suitable material II is adheredto the opposite side thereof by an adhesive IS. The composite sheets maybe stored without adhering to each other and may be quickly applied toany surface by removing the cloth to expose the tacky bottom surface ofthe base I .which is ready for adherence to the surface requiring aphosphorescent material.

The crackle coating 3 of Fig. 7 operates similarly to the coating 3'described in connection with Fig. 6 and disperses the light laterallyand increases the afterglow period.

In the manufacture of the device, the coatings 2, 3 and 4 are appliedand baked consecutively on the surface of an article I. The resultingarticle may be used in the form shown in Fig. 1 or as shown in thepreferred embodiment, the sheet I may then be corrugated or bent into aseries of connected V-shaped or trough-like surfaces as shown in Fig. 4.Preferably, the sides of the V have a small angle with respect to eachother. The device is then ready for attachment to the back or front ofcars or trucks and to any other surface requiring illumination while theordinary illumination thereof is discontinued or ineffective, In theembodiment of Fig. 7, a cloth or other flexible material II is adheredto the bottom of the base I' to facilitate attachment to surfaces.

It will be seen that the present invention provides an improvedphosphorescent device which affords a longer period of afterglow at ahigher intensity than devices known heretofore. The co-mingled rays fromthe adjoining V-shaped surfaces increase the intensity and the periodsof afterglow. The improved coatings increase the efliciency anddurability of the phosphorescent material. The devices are simple inconstruction, inexpensive to manufacture and fully capable ofwithstanding the rough usage to which they may be subjected.

As various changes may be made in the form, construction and arrangementof the parts herein without departing from the spirit and scope of theinvention and without sacrificing any of its advantages, it is to beunderstood that all matter herein is to be interpreted as illustrativeand not in a limiting sense.

Having thus described my invention, I claim:

1. In a phosphorescent device, the combination of a surface having acoating thereon comprising melamine, dibutyl phthalate, toluol, titaniumoxide and aluminum stearate, and a coating of phosphorescent material onsaid first coating.

2. In a phosphorescent device, the combination of a surface having acoating thereon comprising melamine, dibutyl phthalate, toluol andtitanium oxide, a coating of phosphorescent material over said firstcoating and a protective coating over said phosphorescent coating.

3. In a phosphorescent device, the combination of a surface having aphosphorescent coating thereon and a protective coating extending oversaid phosphorescent coating comprising melamine, dibutyl phthalate andtoluol.

4. In a phosphorescent device, the combination of a surface having acoating of phosphorescent material extending over said surfacecomprising melamine, dibutyl phthalate and strontium hydroxide, saidphosphorescent coating being baked for a substantial period to provide ahard permanent surface.

5. In a phosphorescent device, the combination of a surface having acoating thereon and a phosphorescent coating comprising melamine,dibutyl phthalate, toluol and strontium hydroxide extending over saidfirst coating, said phosphorescent coating being baked on.

6. In a device of the class described, the combination of a surfacehaving a coating thereon, a phosphorescent coating extending over saidfirst coating and a protective coating extending over saidphosphorescent coating, said protective coating comprising melamine anddibutyl phthalate.

7. A phosphorescent device, having a surface with a coating thereon, aphosphorescent coating extending over said first coating and bakedthereon and a protective coating comprising melamine and dibutylphthalate extending over said phosphorescent coating and baked thereon.

8. In a device of the class described, the combination of a surfacehaving a coating baked thereon, a phosphorescent coating comprisingmelamine, dibutyl phthalate, and strontium hydroxide extending over saidfirst coating and baked thereon and a protective coating baked on saidphosphorescent coating.

9. A phosphorescent device having a surface and a phosphorescent coatingthereon, said surface having alternate protuberances and depressions toincrease the period and intensity of the afterglow, the coating beingsubstantially uniform in thickness on both said protuberances anddepressions.

10. A phosphorescent device comprising a sheet of material bent into aplurality of flutes, the adjacent sides of said flutes being at acuteangles to each other and a phosphorescent coating thereon having asubstantially uniform thickness.

11. A phosphorescent device having a surface with alternate depressionsand protuberances thereon, a coating on said surface having asubstantially uniform thickness and a phosphorescent coating extendingover said first coating having a substantially uniform thickness,

12. A phosphorescent device comprising a sheet of material bent toprovide a fluted surface, with a. coating thereon having a substantiallyuniform thickness and a phosphorescent coating having a substantiallyuniform thickness extending over said first coating, the adjacentsurfaces of said fluted portion being at an acute angle to each other.

13. A phosphorescent device comprising a sheet of material bent toprovide a fluted surface, a coating thereon, a phosphorescent coatingextending over said first coating and a protective coating extendingover said phosphorescent coating, said coatings being of substantiallyuniform thickness on said fluted surface.

14. A phosphorescent device having a fluted surface with a coatingthereon, a phosphorescent coating extending over said first coating anda protective coating extending over said phosphorescent coating, certainof said coatings being. baked on and all of said coatings having a substantially uniform thickness.

15. A phosphorescent device comprising a sheet of material bent toprovide a fluted surface, a coating thereon, a phosphorescent coatingextending over said first coating, and a protective coating extendingover said phosphorescent coating, all of said coatings being baked onand having a substantially uniform thickness.

16. A phosphorescent device having a surface with a coating thereoncomprising melamine, dibutyl phthalate, toluol, titanium oxide andaluminum stearate; a phosphorescent coating on said first coatingcomprising melamine, dibutyl phthalate, toluol, and strontium hydroxide;and a coating comprising melamine, dibutyl phthalate and toluol on saidphosphorescent coating.

17. A phosphorescent device having a fluted surface with a coatingthereon comprising meiamine, dibutyl phthalate, toluol, titanium oxideand aluminum stearate; a phosphorescent coating on said first coatingcomprising melamine. dibutyl phthalate, toluol, and strontium hydroxide;and a coating comprising melamine, dibutyl phthalate and toluol on saidphosphorescent coating; all of said coatings being baked on.

18. A phosphorescent device having a surface with a phosphorescentcoating thereon, said coating having a crackled finish to increase theperiod and intensity of the afterglow.

19. A phosphorescent device "comprising, in combination, a member havinga phosphorescent crackle finish coating at one side thereof, an adhesiveat another side thereof, and a covering material extending over saidadhesive.

GILBERT T. SCHMIDLING.

